Engine starting mechanism



Nav'. 11, 1941;

original Filed oct. 2, 19,57

nm. mv

v l//JV/l, 4 Imi .MM

INVENTORL Y .l l.\ wv l Patented Nav. 11, 1941 i Romeo M. 'Nardone, Westwood, N. J., assigner, by mesne assignments,`to Bendix yAviation Corporation, South Bend; Ind., a corporation of Dela- Original application October 2, 1937, Serial No. 167,054.` Divided and this application Novem, ber 13, 1940, Serial N0. 365,521

2 Claims. This i invention relates I to engine starting mechanism, and particularly to the type having a rotatable element movable from a normally inoperative position to an 'engine engaging,

position, for producing initial rotary movement of the engine to be started.

An object of the invention is to improve the engine engaging action by the provision of novelcontrol means acting upon the engine engaging element. l

These and other objects ofthe invention will become apparent from inspection of the following specication when read' with reference to the accompanying drawing wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is for the purpose of illustration only, and is not designed as a denitionof the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing:

Fig. 1 is a longitudinal sectional view of a device embodying the invention;

.Fig. 2 is a transverse sectional view along the line 2-2 of Fig. 1; and

Fig. 3 is a. perspective view of the valve assembly.

In the drawing the invention is shown embodied in an engineA starting mechanism of the type utilizing a reciprocable piston contained Within a sectional housing including cylindrical parts I'I and Il), the latter having a ange I2 by which it is secured to the engine crankcase I3 as by bolts I 4. the flange being conveniently of a size standardized for aircraft engine starters. The engine crankshaft, or other drive shaft (not shown) is provided with a clutch element II engageable by the piston actuated c lutch element I5 as will be later more fully described.

4 Cylinder I'I has .ahead end I8 and a crank end 20, the latter being shown as an integral part of a splined tube 2|. Member 20 is shown asabutting flange I6 .of housing section III, and "surrounded by a split clamp 4I,which retains parts I0, I1 and 20 in assembled relationship.

Slidably fitted within the cylinder I1 is a piston 23'rnovab1e with a hollow internally and helically grooved screw 24 which is externally splined as at 25,1 to cooperate with the internally splined tube 2|, a freev sliding action being facilitatedby provision of balls 21. A second Vagainst the tion lreducing balls -36 inserted in the helical grooves 29 and 30. An anti-friction thrust bearing 32 is preferably interposed between a flanged skirt 34 on rear end of spacer 34a and an inwardly extending circular rim 33 of the cylindrical part I 0. The inwardly extending rim 34h on the forward end of spacer 34a takes the thrust as jaw I5 rides into mesh -with engine member II. A spring 31 has one end resting closure plate 20 of the cylinder Il, and its opposite end abuts the thrust ring 38 which moves forward with the piston 23. Piston rings 39 insure against the loss of pressure as the piston moves forward, and also yieldably oppose rotation of the piston, even though twisting of spring 3l should occasionally cause ring 38 to'rotate to some extent (the said ring 38 having a running t about screw 24).

An exhaust valve 42` is adapted to cooperate with an exhaust port 43 conveniently formed in the housing 44, and communicating with an exhaust connection 45 (Fig. 2) leading to any desired point. In the case of an airplane, for example. this exhaust connection will lead to a point exteriorly of the fuselage., The valve 42 iscarrled by a stem 46 which is of such a length that with the piston in theposition indicated in Figure l, a spring 49 will bear against an enlarged head 52 on the stem 46 to hold valve 42 A closed. Into housing there extends a cupshaped grid 40 which receives that` part of the powder charge which is breech into the feed tube 50, said solid charge being then consumedby the generated heat, and l 4 ing the said exhaust valve 42 closed; but as the surrounding the stem 46 will be brought into screw 22 is drivably connected with the screw 24 by helical grooves or threads 23 and 30 which permit the axial travel of the piston 23 but cause `rotation ofthe screw 22 because of fric- 55- circular bead piston nearly reaches the end of its movement, a collar 53 extending inwardly oi.' piston 23 and engagement with the head 52, and will be effective to unseat the exhaust valve 4 2. The exhaust valve having been unseatedl in the manner described, theflngered catch 48 (Figs. 1 and internally formedv 3) will cooperate with the 51 of valve 42 for yieldably holding said valve in open position, its maximum opening movement being likewise limited by the restraining action of the lingers of said element 4l. The neck portion 54 of catch 4I is externally threaded, as shown, for adjustably positionable retention in the housing 44.

`By reason of the action oi.' spring pressed balls propelled from the 58 upon recess 59 in sleeve 22, the initial axial movement of the piston 423 will be transmitted to said sleeve 22, and the resultant axial thrust will be yieldably imparted to jaw I5 through a compressible spring 62 mounted on a rod 63 having at its outer end a nut 64 permitting adjustment of the action of spring 62. Upon re.- sistance to axial travel (as by collision of the tooth corners) spring 62 will permit the continued advance of sleeve 22 under the urge of the balls 58 thereupon. Meanwhile the action of the threads 29, 30 will produce'suicient rotation of sleeve 22 and hence 'of clutch member I5, splined thereto, to relieve the condition of corner tooth contact, whereupon spring 62 becomes effective to complete the meshing (engaging) action. During this operation toroidal spring 'II exerts a radially directed pressure, through leather sealing gasket 12, upon the clutch member I5, producing a friction which prevents too rapid rotation of the member I5, prior to complete meshing, and hence tends to accelerate complete meshing, as well as to insurel a tight sealing of the unit against seepage of oil from the engine crankcase along the surface of the clutch I5, and into the starting apparatus. A cup-shaped element surrounds and supports the member l2, and has a flange adapted to be received between flanges I2 and I3 of the starter and engine, respectively, and is clamped thereto by bolts I4. This cup-shaped element is a further barrier to oil seepage into the starter.

This application is a division of myapplication No. 167,054, iiled October 2, 1937.

What is claimed is:

1. In starting apparatus of the type embodying an engine engaging jaw clutch member, means having engagement with said jaw clutch member both before and during movement of the latter into engagement with a member of the engine to be started, said means including a exible ring of organic material, and means for exerting an inwardly directed pressure on said ring, to seal the space surrounding said jaw clutch member.

2. In starting apparatus of the type embodying an engine engaging jaw clutch member,

means having engagement with said jaw clutch member both before and during movement of the latter into engagement with a member of the engine to be started, said means including a flexible ring of organic material, and means for exerting an inwardly directed pressure on said ring, to seal the space surrounding said jaw clutch member, said means comprising a one-piece resilient element surrounding said ring, and yieldable therewith.

ROMEO M. NARDONE. 

